I am worried about soap contaminating their food and making them sick, so I never wash with soap before feeding my Bettas. In fact, if I've just washed my hands, I will delay their feeding for a while. I will sometimes rinse with just water before feeding them.

Nope. Of course I make sure theres nothing weird on my hands, but I don't ever bother washing my hands before I feed. Though if I feed bloodworms I do wash afterwards because my hands get all bloodwormy. xD

I almost never wash my hands before fiddling with my tanks. Only exceptions are if I have been handling cleaning chemicals with bare hands or have been touching my hospital tank.

Since I don't wear nail polish, perfume or body/hand lotions I don't really see the need to be excessively washing my hands. I am always putting my hands into my tanks so to wash them every single time would just be time consuming.